Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Feb 5th, 2021–Feb 6th, 2021

Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

South Coast Inland.

Continued snowfall and wind will keep storm slabs fresh Saturday. In areas that receive less than 10 cm of new snow, avalanche danger may be a step lower at treeline and below.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Friday night: Cloudy with a few flurries up to 5 cm, moderate to strong westerly ridgetop wind, alpine temperature -8.

Saturday: Snow, around 5 cm in the north and up to 20 in the south, light to moderate westerly ridgetop wind, alpine high -8, freezing level 800 m in the north, 1300 m in the south.

Sunday: Mix of sun and cloud, light variable wind, alpine high -10, freezing level valley bottom.

Monday: Mix of sun and cloud, light variable wind, alpine high -13, freezing level valley bottom.

Avalanche Summary

Loose wet avalanches up to size 2 were reported on Friday, triggered by the sun and running on a shallow crust. Skier triggered wind slabs up to size 1 were reported on Thursday. Throughout the week, there have been reports of natural, explosive and human triggered avalanches size 1-2, including a widespread natural avalanche cycle Monday night. Many of these failed on the recently buried persistent weak layer.

Snowpack Summary

In the south, hot spots around Hope are forecast to receive as much as 20 cm of new snow over the day. In combination with westerly wind, this new snow is likely forming reactive storm slabs in the alpine and open treeline areas. In the north, localized wind slabs are forming over a crust on solar aspects as westerly winds redistribute recent snow into leeward terrain features.

30-80 cm of recent snow sits on a persistent weak layer that consists of facets at upper elevations, surface hoar in sheltered areas, a melt-freeze crust below 1600 m, and a sun crust on south-facing slopes. 

In the south, the underlying snowpack is well consolidated. In the north, a melt-freeze crust from early December may be found 100 to 200 cm deep. Recent reports suggest that this layer is gaining strength and it has been unreactive in recent weeks.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Avoid freshly wind loaded terrain features.
  • Be aware of highly variable recent wind loading patterns.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.